1. Field of the Invention
The present invention relates to a hand orthosis or orthopedic device for providing finger prehension for a cervical 6 -- cervical 7 motor lesion quadraplegic.
2. Description of the Prior Art
If a human motor nerve is injured, the effect is to cut off the output signals from the spinal chord and higher centers to the effector tissues (the muscles) which the injured nerve supplied. Very limited and circumscribed lesions in the spinal chord may involve a motor or sensory side of the input-output system with loss of motor control. Spinal chord injuries may be partial or complete, and location of the injury determines the extent of the loss of motor control. Typically, cervical 6 -- cervical 7 motor nerve lesions result in loss of motor control of the legs and portions of the arms. However, typically, depending on the extent of the injury, a cervical 6 -- cervical 7 motor lesion quadraplegic retains some control over the movement of the arms but loses control over movement of the hands and fingers. Thus, while the cervical 6 -- cervical 7 motor lesion quadraplegic can move his or her arm, it is impossible to grasp objects with the fingers.
An orthosis or othetic device is a brace or other orthopedic device which is applied to the body in the treatment of physical impairment or disability. Orthopedic devices to control and operate a paralysed hand to permit the paralysed hand to pick up articles and objects are known in the art. For example, U.S. Pat. No. 2,553,277 - Robinson et al., discloses a control and operating means for paralyzed hands. In addition, U.S. Pat. No. 2,893,016 - Zion discloses a prosthetic device forming an artificial hand for use by the patient whose hands do not function normally. Further, U.S. Pat. No. 3,707,963 - Keropian discloses an articulated hand brace for articulating a disabled or paralyzed hand.
Various other prosthetic and orthopedic devices are well known in the art. However, one problem experienced with prior art prosthetic and orthotic devices is providing a control mechanism that is easily operable by the patient. Typically, quadraplegics and other disabled individuals have a very limited ability to provide the necessary muscular control to activate a mechanism to control the prosthetic or orthotic device. For example, U.S. Pat. No, 3,769,636 -- Friedman discloses an orthotic brace using the head orientation of the patient to control the device. Thus, by movement of the patient's head in various directions, the articulation of the device is controlled. However, this device is relatively expensive and unnecessary where the patient has some muscular control of the arm such as in the case of a cervical 6 - cervical 7 quadraplegic.
Similarly, U.S. Pat. No. 3,683,423 -- Krapanzano discloses a gravity actuated prosthetic device utilizing a control mechanism using gravity sensitive mercury switches for control purposes. However, this device is dependent upon the position and orientation of the prosthetic device itself to initiate operation of the device which may not be compatible with the activity desired by the patient.
Orthopedic and orthotic devices are typically designed so that the patient operates the device with the arm opposite the arm being controlled. This limitation prevents the patient from being equipped with such an orthotic device on each arm and hand so that each hand can be controlled.
Thus, it would be a desirable advance in the art to provide a hand orthosis for providing finger prehension for a cervical 6 - cervical 7 motor lesion quadraplegic that can be controlled by the same arm to which the device is attached so that the patient may be equipped with an orthosis for each arm. Further, it would be a desirable advance in the art to provide an activating means for such an orthosis which will require no force from the patient to initiate operation. In addition, since a cervical 6 - cervical 7 motor lesion quadreplegic is typically equipped with a battery operated wheelchair for movement, it would be a desirable advance in the art to provide an orthosis which can be attached to the wheelchair and powered by the same battery as the wheelchair.